Treatment of ore.



UNITED STATES PATENT OFFICEQ GUY DE BEGI'II, OF PARIS, FRANCE.

TREATMENT OF ORE.

SPECIFICATION forming part of Letters Patent No. 652,072, dated June 19,190 0.

Application filed January 24:, 1898. Serial No. 667,795. (No specimens.)

To all whom, it puny concern/.-

Be it known that I, GUY DE BECHI, a subject of the King of Italy,residing at the city of Paris, France, have invented a certain new anduseful Improvement in the Treatment of Ores Containing Intimately-MixedCopper, Zinc, and Lead, (for which I have received a patent in France,dated July 5, 1897;) and I do hereby declare that the following is afull, clear, and exact description of the invention, which will enableothers skilled in the art to whichit appertains to make and use thesame.

This invention relates particularly to the treatment of ores consisting,of complex mixtures of blende, galena, and copper pyrites which it isnot generally possible to separate by mechanical treatment. My inventionis, however, equally applicable to the treatment of complex orescontaining zinc and lead, but not copper. The metallurgical treatment ofores of this kind has heretofore been so expensive as to prevent suchtreatment coming into practical use. The object of my invention is toovercome this difficultyand to enable nearly the whole of the copper andthe greater portion of the zinc and lead to be extracted in acommercially-pure state and in an economical manner.

According to my invention I treat ores of the kind referred to in thefollowing manner: The pulverized ore is mixed with from twenty to fortyper cent. of its Weight of ordinary salt (chlorid of sodium) or anywaste salt rich in alkali metal chlorids or alkali earth metal chlorids,(such as calcium chlorid or magnesium chlorid,) and is then subjected toa chlo= ridizing roasting in furnaces, such as are usually employed inmetallurgy for this purpose. The gaseous products formed in the reaction(hydrochloric acid, sulfurous and sulfuric anhydrides, chlorin, &c.,) asalso the metallic salts carried off in the process by volatilization,are condensed in suitable towers. The product remaining in the furnacesthen comprises the major portion of the zinc and copper in the form ofsalts soluble in water, a certain quantity of these metals in the formof oxids, and a small quantity of the sulfids of said metals whichremain unaltered. The product is treated with a solution of calciumchlorid obtained during the working of this process, as hereinafterdescribed, and is then lixiviated with the acid ulated Waterproduoed inthe above-mentioned condensing-towers. Any sulfuric acid or solublesulfates contained in such acidulated Water or in the roasted ore aredecomposed by the addition of calcium chlorid,insoluble sulfate of limebeing formed. This acidulated water dissolves the: oxids of copper andzinc. This lixiviation of the roasted ore may be carried out at thenormal temperature. It is, however, preferable to heat the liquid-forexample, by injecting thereinto warm air or a mixture of air and steam.The greater part of theiron present in the ore is thus transformed intoan insoluble ferric subsalt.

By the above treatment a solution is obtained which contains thechlorids of copper, zinc, sodium, and calcium, and a certain quantity offree hydrochloric acid. Nearly the whole of the lead contained in theore and of the sulfates formed in the roasting process remain in theinsoluble state with the residue of the lixiviation. The solution isneutraized with lime and is heated to the boiling-point. A quantity ofhydrated oxid of zinc, derived from a preceding operation, is then addedto the solution, whereupon the copper is precipitated in the form ofhydrated oXid of copper, the zinc replacing the copper in accordancewith the equation Z11O2H2 (hydrated oxid of zinc) CuCL, (cupric chlorid)0110 13 (hydrated oxid of copper) ZnCl,, (zinc chlorid.) This separationof the copper in the state of hydrated oxid may also be effected byadding to the neutral solution a quantity of lime sufficient only tocombine with the acid radical of the copper salt, so that the zinc isnot precipitated. It is of course understood that the lime may bereplaced by sodium hydrate, sodium carbonate, (soda ash,) or likesubstances that will cause the precipitation of the copper before thatof the zinc.

When the whole of the copper has been precipitated, the precipitate ofhydrate of copper is separated, by means of a. suitable filter, from thesolution, and to the filtrate, which now only contains zinc to theexclusion of any other heavy metal, is added the quantity of lime orother alkali necessary for combining with the acid radical of the zincsalt and precipitating the zinc in the form of hydrated oXid of zinc. Ifno copper is con- Ice tained in the ore under treatment, theabovementioned step in my process for the precipitation thereof will ofcourse be omitted. These fractional precipitations are advantageouslycarried out With a hot solution. They may, however, be performed at thenormal temperature, care being taken to maintain the liquid in contactWith the reagent by means of an energetic and prolonged agitation. Theliquid containing the hydrate of zinc in suspension is filtered, thefiltrate then containing only sodium chlorid and calcium chlorid. Bypartial evaporation of the filtrate the sodium chlorid is recovered andis utilized over again in the process, and a solution is obtained highlycharged with calcium chlorid, which solution, as before stated, servesfor the treatment of a fresh quantity of roasted ore to eliminatesoluble sulfates therefrom.

The hydrated oxid of copper obtained by the treatment above describedmay be converted into sulfate of copper or reduced to metallic copper inthe usual manner. The hydrated oxid of zinc may be reduced to metalliczinc by any appropriate process. Finally the residue of the lixiviation,which contains the lead and all the impurities of the ore, is treated ina cupola-furnace with a suitable flux and metallic lead thus obtained.

What I claim is 1. The method of treating com plex ores for the recoverytherefrom of copper, zinc and lead, consisting in subjecting the saidore to a chloridizing roasting, treating the roasted ore with a solutionof calcium chlorid to remove soluble sulfates, lixiviating the ore toremove zinc and copper, and fractionallyprecipitating the zinc andcopper from the solution, as hydrated oxids, substantially as described.

2. The method of treating complex ores for the recovery therefrom ofcopper, zinc and lead, consisting in subjecting the said ore to achloridizing roasting, treating the roasted ore with a solution ofcalcium chlorid to remove soluble sulfates, lixiviating the ore toremove zinc and copper, and fractionally precipitating the zinc andcopper from the solution as hydrated oxids by successive additions of analkali metal salt, substantially as described.

3. The method of treating complex ores, consisting in subjecting the oreto a chloridizing roasting, condensing the vapors and gases evolved,treating the roasted ore and the acidulated Water containing thecondensed vapors and gases with calcium chlorid to precipitate solublesulfates and sulfuric acid as insoluble calcium sulfate, then lixiviating the ore with the acid ulated water to obtain a solution of zinc andcopper salts, and fractionally precipitating zinc and copper from thesaid solution as hydrated oxids by successive additions of lime,substantially as described.

In testimony whereof I sign this specification in the presence of twosubscribing witnesses.

G. DE BECHI. Witnesses:

WILLIAM II. MADDEN, KATOHEN STENZ.

